Testing for Equivalence of Means under Heteroskedasticity by an Approximate Solution of a Partial Differential Equation of Infinite Order

Abstract. A test for two‐sided equivalence of means has been developed under the assumption of normally distributed populations with heterogeneous variances. Its rejection region is limited by functions ± h that depend on the empirical variances. h is stated implicitly by a partial differential equation, an exact solution of which would provide a test that is exactly similar at the boundary of the null hypothesis of non‐equivalence. h is approximated by Taylor series up to third powers in the reciprocal number of degrees of freedom. This suffices to obtain error probabilities of the first kind that are very close to a nominal level of α = 0 . 05 at the boundary of the null hypothesis. For more than 10 data points in each group, they range between 0.04995 and 0.05005, and are thus much more precise than those obtained by other authors.     

Partial sufficient dimension reduction on joint model of recurrent and terminal events

Joint modeling of recurrent and terminal events has attracted considerable interest and extensive investigations by many authors. The assumption of low-dimensional covariates has been usually applied in the existing studies, which is however inapplicable in many practical situations. In this paper, we consider a partial sufficient dimension reduction approach for a joint model with high-dimensional covariates. Some simulations as well as three real data applications are presented to confirm and assess the performance of the proposed model and approach.     

Non‐parametric interval estimation for the partial area under the ROC curve

Accurate diagnosis of disease is a critical part of health care. New diagnostic and screening tests must be evaluated based on their abilities to discriminate diseased conditions from non‐diseased conditions. For a continuous‐scale diagnostic test, a popular summary index of the receiver operating characteristic (ROC) curve is the area under the curve (AUC). However, when our focus is on a certain region of false positive rates, we often use the partial AUC instead. In this paper we have derived the asymptotic normal distribution for the non‐parametric estimator of the partial AUC with an explicit variance formula. The empirical likelihood (EL) ratio for the partial AUC is defined and it is shown that its limiting distribution is a scaled chi‐square distribution. Hybrid bootstrap and EL confidence intervals for the partial AUC are proposed by using the newly developed EL theory. We also conduct extensive simulation studies to compare the relative performance of the proposed intervals and existing intervals for the partial AUC. A real example is used to illustrate the application of the recommended intervals. The Canadian Journal of Statistics 39: 17–33; 2011 © 2011 Statistical Society of Canada     

Identifying Treatment Effects Under Data Combination

We consider the identification of counterfactual distributions and treatment effects when the outcome variables and conditioning covariates are observed in separate data sets. Under the standard selection on observables assumption, the counterfactual distributions and treatment effect parameters are no longer point identified. However, applying the classical monotone rearrangement inequality, we derive sharp bounds on the counterfactual distributions and policy parameters of interest.     

A Practical Two‐Step Method for Testing Moment Inequalities

This paper considers the problem of testing a finite number of moment inequalities. We propose a two‐step approach. In the first step, a confidence region for the moments is constructed. In the second step, this set is used to provide information about which moments are “negative.” A Bonferonni‐type correction is used to account for the fact that, with some probability, the moments may not lie in the confidence region. It is shown that the test controls size uniformly over a large class of distributions for the observed data. An important feature of the proposal is that it remains computationally feasible, even when the number of moments is large. The finite‐sample properties of the procedure are examined via a simulation study, which demonstrates, among other things, that the proposal remains competitive with existing procedures while being computationally more attractive.     

Entropic Latent Variable Integration via Simulation

This paper introduces a general method to convert a model defined by moment conditions that involve both observed and unobserved variables into equivalent moment conditions that involve only observable variables. This task can be accomplished without introducing infinite‐dimensional nuisance parameters using a least favorable entropy‐maximizing distribution. We demonstrate, through examples and simulations, that this approach covers a wide class of latent variables models, including some game‐theoretic models and models with limited dependent variables, interval‐valued data, errors‐in‐variables, or combinations thereof. Both point‐ and set‐identified models are transparently covered. In the latter case, the method also complements the recent literature on generic set‐inference methods by providing the moment conditions needed to construct a generalized method of moments‐type objective function for a wide class of models. Extensions of the method that cover conditional moments, independence restrictions, and some state‐space models are also given.     

语境对疑问表否定用法的制约性研究

语境在具体上下文中对答案的显著性造成影响,因此,某一语言表达成为隐喻的第一要素是从语用角度或从语境角度看,它和语境要有明显不合之处。疑问句表否定的用法就是建立在同语境不合的基础上,所以要想真正理解其否定含义,就离不开语境。语境所包含的世界的知识、对话双方的知识、上下文知识和场景知识等因素往往是综合在一起来实现某种作用的。语境对表判断的陈述性含义、其他陈述性含义和表示指令性的含义三种答案的显著性有不同程度的影响。一般否定句对命题的否定是显性的,一般不需要语境来实现理解,而表否定的疑问句由于形式上常常同一般问句基本一致,对命题的否定是隐性的,因此后者对语境的依赖程度很大,要理解疑问句是否表示否定,就离不开语境。     

非规约间接否定言语行为的分类

非规约间接否定言语行为指形式和字面意义为肯定但含意和命题态度为否定的一种语用策略。以关联理论对意义的划分为标准,非规约间接否定言语行为可分为显义、预设和寓义三大类。显义包括指称指派类和命题意义类;预设包括语义预设类和语用预设类;寓义包括一般寓义类和弱寓义类。     

莎剧中的性别意识与性政治

莎士比亚的性别意识包含对女性的否定,视女性为身体和精神有缺陷的性别,认同两性关系上的统治逻辑,且在剧中有女性内化为自我否定的因素;对女性的贬斥和赞誉在思想上同源于男权支配女性的意识;认同对女性身体施加的否定的文化意涵,张扬自然性别之外的文化性别状态,并导向对女性主体性的否定。莎氏这种性别意识承袭了西方的性政治传统,并经由戏剧文本呈现出性别统治的权力本质。     

普通否定与含意否定

本文论述了英语中两种不同的否定现象,即普通否定与含意否定。研究了其区别,阐述了这两种否定内在的解读机制,并讨论了含意否定与传统语法之间的关系。